Dynamic loading influences material properties as well as the behavior of structures. In dynamic tests on structural steels with different rates of strain, both yield stress and yield strain increase with an increase in strain rate. The increase in yield stress is significant for A36 steel in that the average dynamic yield stress reaches 41.6 ksi for a time range of loading between 0.01 and 0.1 sec. The strain at which strain hardening begins also increases, and in some cases the ultimate strength can increase slightly. In the elastic range, however, the modulus of elasticity typically remains constant. (See Art. 1.11.)
